Thank you for your reply! And I had figured out why it didn't work. You are right. My frame buffer was empty. To solve this problem, I just put the getPixels() method in the onDrawFrame like this:```public int[] tmpPixels;// Global variancepublic void onDrawFrame(GL10 gl) { tmpPixels = fb.getPixels(); fb.clear(back);

} catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); }}```And it works! By the way, obviously, the program becomes extremely slow by using tmpPixels to record the pixel of image on onDrawFrame in this way. Of course I will use some flags to control this process. Thanks again!